A network for communications, including for cable television, phone, and internet data traffic, typically includes a base station, one or more head-ends, one or more intermediate hubs, and the subscriber facilities. The subscriber facilities typically represent the end of the line and include one or more modems, routers, and the consuming technology—phones, televisions, computers, laptops, electronic tablets, smartphones, InternetOfThings (IoT) devices, and other internet-enabled devices.
Receivers may have digital components working together with analog components as a system-on-a-chip (SoC). Typically, there are many different synthesizers and clock sources in digital and analog components. Even with good layout and circuit design for a printed circuit board (PCB), undesired leaking of tone signals occurs toward the analog front-end features from other circuit and chip components, such as, the crystal oscillator, digital clocks, and synthesizers. These undesired tone signals may also be inside the desired signal bandwidth for these circuit and chip components. Certain system may use a band-stop filter to filter the undesired tone signals, but such implementations filter the desired signal as well.
In certain schemes, an undesired signal is supressed before the noisy signal is passed through an analong-to-digital convertor (ADC) so that the undesired signals are not present in the digital signal. This, however, adds extra complexities and cost. In some implementations using these schemes, it is impossible to detect all of the undesired signals in the analog domain. As a result, additional steps are needed to redesign the circuits after detecting the tone signals in the digital domain in order to suppress them in the analog domain.